BACTERIAL AND FUNGAL CONTAMINANTS OF TISSUE-CULTURED 'LAKATAN' BANANA

This study aimed to characterize the bacterial and fungal contaminants of tissue-cultured 'Lakatan' banana (Musa acuminata) during initiation stage. This was conducted at the University of Southeastern Philippines, Tagum-Mabini Campus from October 2015 to February 2016. The sterilized banana explant was placed in a bottle of solidified nutrient agar medium. Detectable bacterial and fungal contaminants were isolated and sub-cultured into the fresh medium two to four days after incubation. The bacterial isolates were cultivated by streaking into fresh culture medium and incubated at 0 0 30-32 C for three days and fungi culture disk was transferred to fresh culture medium and incubated at 30-32 C for three to five days. Both bacterial and fungal contaminants were identified and characterized and assessed for extent of contamination. Results showed that the different contaminants occurred during the initiation stage of tissue-cultured 'Lakatan' banana meriplants were composed of Rhizopus sp., unidentified fungus and Gram-negative bacterium. Generally, 35% contamination was observed on this stage.

ISOLASI, IDENTIFIKASI, DAN SKRINING JAMUR ENDOFIT PENGHASIL AGEN BIOKONTROL DARI TANAMAN DI LAHAN PERTANIAN DAN HUTAN PENUNJANG GUNUNG SALAK

Isolation of endophytic fungi was done to find alternative microorganisms as biocontrol agents against Rhizoctonia solani Kuhn, a soil borne pathogen on many agriculturalcrops. The research objectives were 1) to isolate and identify endophytic fungi colonize plants growing on agricultural and Mount Salak supporting forest lands in the Villages of Parakan Salak and Cimalati, Sukabumi; and 2) to screen for their biocontrol agent activity againt R. solani. Diameter of R. solani was measured on day 2 after inoculation, and its percent inhibition of growth by endophytic fungi is calculated using the formula Skidmore & Dickinson (1976). The results indicated that 214 isolates of endophytic fungi were isolated from 96 plant species that growing in both places. Endophytic fungi isolated including in the group of Aspergillus, Cladosporium, Colletotrichum, Curvularia, Drechslera, Fusarium, Guignardia, Mucor, Nigrospora, Paecilomyces, Penicillium, Pestalotiopsis, Phoma, Phomopsis, Rhizoctonia, and endophytic fungi that have not been identified. Of the 214 fungal isolates tested, 39 isolates (18.22 %) could inhibit the growth of R. solani from 10.18 % to 58.99 % with a percent inhibition. The highest growth inhibition of R. solani were shown respectively by an unidentified fungus isolatedfrom Hyptis capitata Jack (58.99%), Cladosporium sp. isolated from jeruk bali (Citrus grandis (L.) Osbeck) (55.42%), Pestalotiopsis sp. isolated from pine apple (Ananas comosus (L.) Merr.) (53.85 %), and Paecilomyces lilacinus (Thom) Samson isolated from banyan (Ficus benyamina L.) (51.81%)